/*
 * Copyright (C) 2010 Cyril Mottier (http://www.cyrilmottier.com)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package greendroid.widget;

import greendroid.util.Config;
import greendroid.widget.SegmentedBar.OnSegmentChangeListener;
import android.content.Context;
import android.content.res.TypedArray;
import android.database.DataSetObserver;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.LinearLayout;

import com.cyrilmottier.android.greendroid.R;

/**
 * A SegmentedHost is a wrapper view that handle a SegmentedBar and a
 * FrameLayout that hold the content. Data (titles, and content Views) are
 * provided to the SegmentedHost via a {@link SegmentedAdapter}.
 * 
 * @author Cyril Mottier
 */
public class SegmentedHost extends LinearLayout {

	private final static String LOG_TAG = SegmentedHost.class.getSimpleName();

	private int mSegmentedBarId;
	private SegmentedBar mSegmentedBar;
	private int mSegmentedHostId;
	private FrameLayout mContentView;
	private int mSelectedSegment;

	private SegmentedAdapter mAdapter;
	private View[] mViews;
	private DataSetObserver mSegmentObserver = new DataSetObserver() {

		public void onChanged() {
			setupSegmentedHost(mSelectedSegment);
		}

		public void onInvalidated() {
			// Do nothing - method never called
		}
	};

	public SegmentedHost(Context context) {
		this(context, null);
	}

	public SegmentedHost(Context context, AttributeSet attrs) {
		this(context, attrs, R.attr.gdSegmentedHostStyle);
	}

	public SegmentedHost(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs);
		initSegmentedView();

		TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.SegmentedHost, defStyle, 0);

		mSegmentedBarId = a.getResourceId(R.styleable.SegmentedHost_segmentedBar, -1);
		if (mSegmentedBarId <= 0) {
			throw new IllegalArgumentException("The segmentedBar attribute is required and must refer " + "to a valid child.");
		}

		mSegmentedHostId = a.getResourceId(R.styleable.SegmentedHost_segmentedContentView, -1);
		if (mSegmentedHostId <= 0) {
			throw new IllegalArgumentException("The segmentedHost attribute is required and must refer " + "to a valid child.");
		}
	}

	private void initSegmentedView() {
		setOrientation(LinearLayout.VERTICAL);
	}

	@Override
	protected void onFinishInflate() {
		super.onFinishInflate();

		mSegmentedBar = (SegmentedBar) findViewById(mSegmentedBarId);
		if (mSegmentedBar == null) {
			throw new IllegalArgumentException("The segmentedBar attribute must refer to an existing child.");
		}
		mSegmentedBar.setOnSegmentChangeListener(new SegmentSwitcher());

		mContentView = (FrameLayout) findViewById(mSegmentedHostId);
		if (mContentView == null) {
			throw new IllegalArgumentException("The segmentedHost attribute must refer to an existing child.");
		} else if (!(mContentView instanceof FrameLayout)) {
			throw new RuntimeException("The segmentedHost attribute must refer to a FrameLayout");

		}
	}

	public SegmentedBar getSegmentedBar() {
		return mSegmentedBar;
	}

	public FrameLayout getContentView() {
		return mContentView;
	}

	public void setAdapter(SegmentedAdapter adapter) {

		if (mAdapter != null) {
			mAdapter.unregisterDataSetObserver(mSegmentObserver);
		}
		mAdapter = adapter;

		if (adapter != null) {
			mAdapter.registerDataSetObserver(mSegmentObserver);
		}
		setupSegmentedHost(0);
	}

	private void setupSegmentedHost(int selectedSegment) {

		if (Config.GD_INFO_LOGS_ENABLED) {
			Log.i(LOG_TAG, "Preparing the SegmentedHost with the segment " + selectedSegment);
		}

		mSegmentedBar.removeAllViews();
		mContentView.removeAllViews();
		mViews = null;

		if (mAdapter != null) {
			// Add all segments to the Segmentedbar
			final int count = mAdapter.getCount();
			for (int i = 0; i < count; i++) {
				mSegmentedBar.addSegment(mAdapter.getSegmentTitle(i));
			}

			if (selectedSegment < 0) {
				selectedSegment = 0;
			} else if (selectedSegment > count) {
				selectedSegment = count;
			}

			if (count > 0) {
				// Prepare the SegmentBar
				mViews = new View[count];
				mSegmentedBar.setCurrentSegment(selectedSegment);

				// And displays the first view
				setContentView(selectedSegment);
			}
		}
	}

	private class SegmentSwitcher implements OnSegmentChangeListener {
		public void onSegmentChange(int index, boolean clicked) {
			setContentView(index);
		}
	}

	private void setContentView(int index) {
		mSelectedSegment = index;
		mContentView.removeAllViews();
		if (mViews[index] == null) {
			mViews[index] = mAdapter.getView(index, SegmentedHost.this);
		}
		mContentView.addView(mViews[index]);
	}

}
